They said the health service was not set up to care for the needs of rising numbers of patients suffering chronic conditions, often fuelled by unhealthy lifestyles.

Millennials are set to be the fattest generation on record, with obesity causing nine in ten cases of type two diabetes.

Prof Melanie Davies, from the University of Leicester, said: “There are now over 500 children with type two diabetes . A child or adolescent with type two diabetes was almost unheard of just 20 years ago.”

“Within a generation it has changed really quickly,” said the professor of diabetes medicine, describing the rate of increase as “scary”.

Prof MacMahon said GP consultations were too short to allow them to properly care for patients with several diseases.

“We are facing a tidal wave of patients living with multiple long-term health conditions, and our report demonstrates how little we know about how to manage this,” he said.

“It’s extremely difficult to manage a patient with half a dozen diseases in 10 minutes. What happens is multiple consultations each focusing on the individual diseases, “ he said.

The average person aged 65 is likely to have three or more conditions, researchers said – rising to between five and seven among those aged 85 and over.

Dr Lynne Corner, from the Newcastle University Institute for Ageing and Faculty of Medical Sciences said health services needed to be reorganised around the needs of those with multiple health conditions.

“It can be a full time job being a patient,” she said. “It’s not unusual for someone to have five different appointments on five different days with five different teams and that can be really difficult to manage.”